An electron with kinetic energy E collides with a hydrogen atom in the ground state. The collision will be elastic

Question

An electron with kinetic energy E collides with a hydrogen atom in the ground state. The collision will be elastic (A) for all values of E (B) for E < 10.2 eV (C) for 10.2 eV < E < 13.6 eV only (D) for 0 < E < 3.4 eV only

Tardigrade Admin · Accepted Answer

First excitation energy of a hydrogen atom in ground state is

10.2 e V

.

So, if energy of colliding electron is more than

10.2 e V

, then hydrogen atom absorbs

10.2 e V

from kinetic energy of electron and collision will be inelastic.
If energy of electron is less than

10.2 e V

, then hydrogen atom does not absorbs energy and total energy before and after collision remains same and collision will be elastic.

Q. An electron with kinetic energy E collides with a hydrogen atom in the ground state. The collision will be elastic

for all values of E

for E < 10.2 eV

for 10.2 eV < E < 13.6 eV only

for 0 < E < 3.4 eV only

Q. An electron with kinetic energy $E$ collides with a hydrogen atom in the ground state. The collision will be elastic